A sewing machine is known having a sewing surface along which the workpiece passes through a sewing station. A fixed guide element has guide edge extending parallel to the workpiece path next to the station and a cover element spaced above the surface and displaceable between an operative position overlying the path and overhanging the guide edge to define with this guide edge and with this sewing machine workingsurface a guide slot, and an inoperative position lying outside the path in back of the guide edge. A pneumatic cylinder serves to displace this cover element between these two positions and is coupled to the sewing machine drive so that the cover element is in its operative position when the machine is operating at high speed but is displaced into an inoperative position when the machine is operated at low speed for precise stitching or loading. Such a machine is described in the above cited patent.
A feed device is known which has a clip that engages the side or back edge of a workpiece being pulled by the sewing machine workpiece advance through the stitching station. This clamp or clip serves to hold a pair of workpieces together and maintains the workpiece relatively taut between the sewing station and the trailing edges of the workpieces. It is known to provide a single clip that grips the trailing edge of the workpiece, or a plurality of clips which engage the sides and/or trailing edges.
Such arrangements all have the considerable disadvantage that the attachment of the workpiece to be stitched to the clip or clips is z relatively time-consuming operation. In addition between subsequent stitching operations the necessary time to load in another workpiece is relatively long. Furthermore, such feed devices are often relatively complicated and difficult to master for the sewing-machine operator.